Comedian Eddie Murphy brings his "Pieces of My Mind" act to the Pacific Amphitheatre tonight at 7:30. Murphy, who found fame as a regular cast member of television's "Saturday Night Live" and went on to movie stardom in such films as "Trading Places" and "Beverly Hills Cop," will stick to comedy in tonight's show despite last year's successful foray into pop music. His album, "How Could It Be," spawned a top-5 single, "Party All the Time." Tonight's show at the Pacific is the only scheduled Los Angeles-area appearance in the comedian's current U.S. tour. Appearing with Murphy in Costa Mesa will be the pop group the Weather Girls, who had a recent hit single with "It's Raining Men."